Timeouts fix and abort mainloop correctly.

Go 1.1 means we can set timeouts on HTTP clients correctly.  Do so.

Goroutine profile showed many instances of spiderMainLoop -- the `break`
statement only exited the inner switch, not the function.  Use a
`return` instead.
Change default -keys-daily-jitter 500 => 800

Post-PRISM, OpenPGP has become somewhat more popular.